The protracted economic downturn is putting pressure on that assumption. Speak with enough experts on negotiation--people who have worked on everything from the Iran hostage crisis to multimillion-dollar corporate deals—and one thing is very clear: Nearly everything is negotiable. Especially if you have some haggling chops.

“People don’t have what I call a ‘negotiation consciousness’,” says Ed Brodow, author of Negotiation Boot Camp, who has trained employees at Microsoft, Goldman Sachs and the Pentagon. “You have to be prepared to challenge things---that’s the biggest hurdle.”

No matter what’s being negotiated, there are two rules any would-be haggler must follow.

First, make sure that you’re dealing with the right person—someone who actually has the authority to grant concessions. Do your best to understand how that person is incentivized and tailor the deal accordingly. For example, sales people are often willing to budge on price when it means they’ll see a commission, while small businesses place a higher value on loyalty and customer referral.

“The only reason that people make a deal is because it’s in their interest,” says Mladec Kresic, President of K&R Negotiation Associates, a consulting firm that has guided negotiations for Kodak, Sun Microsystems, and IBM.

Second, always be willing to walk away. You’ll project “confidence and power,” says Dr. William Ury, co-author of Getting to Yes and Senior Fellow at the Harvard Negotiation Project, a research group that studies ways to improve conflict resolution. Being committed to walking away will keep you from getting emotionally involved in a deal, the number one downfall of most negotiators.

In the end though, there’s no substitute for a friendly disposition and a disarming wit. As Brodow says: “If people like you, they will help you.”

Here are a handful of items that, with a little skill, moxie and luck, you can get for less than advertised. (For a full list of 19, see our slideshow.)

Electronics

The strategy: Go for floor models if possible. Understand, too, that anything the store is willing to put on sale is ripe for negotiation. An even more sophisticated approach: Figure out which version of a particular product the store is missing and use that information to negotiate a lower price. Example: If a store doesn’t carry a white digital camera, make it known that you would have preferred the camera in white and that by settling for different color, you’re making a serious concession---one that should be reflected in how much you pay for it.

Potential savings: up to 40%

Furniture

The strategy: See the previous slide on electronics. For an extra edge, look for small defects that don’t really bother you but that might fluster a floor manager or two. In this housing market, they may be happy just to keep their inventory moving, even at a lower price. To wit: Annual revenue at Furniture Brands, maker of the Broyhill, Lane and Thomasville lines, is projected to drop for a fifth straight year, to $1.15 billion, in 2011, according to the average of analysts’ estimates compiled by Bloomberg.